PinX1 regulates the G1/S phase transition and cell proliferation through the p16/cyclin D1 pathway in UCB cells. Flow cytometric analysis of the (A) EJ bladder urothelial carcinoma cells infected with vector or PinX1, (B) T24 bladder urothelial carcinoma cells infected with vector or PinX1, and (C) 5637 cells infected with RNAi-vector or PinX1-shRNA. (D) The seven genes, CDKN2A (i.e. p16), CDKN2B (i.e. p15), GADD45A, CCND1 (i.e. cyclin D1), CCND2 (i.e. cyclin D2), ANAPC2 and CDK5R1), were examined >2-fold mRNA differential expression in PinX1-transfected T24 cells compared with that of scramble vector transfected by using a Human Cell Cycle RT2 ProfilerCC PCR Array. (E) Overexpression of PinX1 substantially upregulated p16 expression and downregulated cyclin D1 expression in T24 cells detected by western blotting. *P < 0.05, **P < 0.01.